The present invention relates to a vacuum sampling tube to be used in the so-called vacuum sampling system for collection of specimens which are aspiratable by utilizing a pressure difference between the inside and outside of the tube and a vacuum sampling method using said vacuum sampling tube. Above all else, the invention relates to a vacuum blood collecting tube for use in clinical examinations to be performed on blood specimens and a vacuum blood collecting method using said blood collecting tube.
While a typical vacuum blood collecting system is described in Japanese Kokai Publication Sho-62-227316, the fundamental construction of the system comprises:
1) as illustrated in FIG. 12, a vacuum blood collecting tube 30 comprising a bottomed tubular casing 32 and a plug 31 having needle hole-sealable, gas-barrier properties as sealing the open end of said casing gas-tight to thereby keep a negative pressure within said casing;
2) as illustrated in FIG. 13, a vacuum blood collecting needle 40 comprising a hollow needle of metal having needle tips 41 and 42 at both ends and a hub 43 provided with a male thread 44 on the plug-piercing side; and
3) as illustrated in FIG. 14, a holder for vacuum blood collection 50 having a blood collecting needle-retaining aperture 51 provided with a female thread engageable with the male thread of said hub 43 so that said vacuum blood collecting tube 30 may be accepted into an internal cavity 52.
In blood collecting, the vacuum blood collecting needle 40 is threaded onto the blood collecting needle-retaining aperture 51 of the holder for vacuum blood collection 50. Then, the vacuum blood collecting tube 30 is inserted into said holder 50 and forced against the needle tip 42 of the vacuum blood collecting needle 40 to the extent that the plug 31 is not completely pierced through so as to temporarily seal the needle tip 42. This is done to prevent the blood from leaking out of the needle tip 42 when the needle tip 41 is inserted into a blood vessel.
The person in charge of blood collection holds the whole of said blood collecting needle/said holder/said blood collecting tube assembly by hand in an incumbent position along the axis of the subject""s blood vessel and sticks the needle tip 41 on the blood vessel piercing side into the blood vessel. Then, as he or she advances said blood collecting tube 30 farther into said holder 50, the needle tip 42 on the plug piercing side penetrates through the plug 31, with the result that the blood flows into said blood collecting tube due to the pressure difference between the blood collecting tube side and the blood vessel side. Then, as the pressure difference is abolished, the blood inflow stops. Therefore, the whole assembly is withdrawn from the blood vessel to complete a blood collecting work.
Usually, depending on the object of an examination, said blood collecting tube involves a coagulation accelerator, an anticoagulant, a deproteinizing agent, a blood component stabilizer, and/or the like for the pretreatment of a blood specimen in its inside. However, since these drugs denature the blood into a nonphysiological state different from its state in vivo, the risk of these chemicals finding their way into the subject""s body in the event of a backflow by mistake during blood collecting has been pointed out.
For the prevention of such a backflow, Japanese Kokai Publication Sho-49-51784 and Japanese Kokai Publication Sho-50-12892 each proposes a vacuum blood collecting needle provided with an elastic backflow prevention valve and Japanese Kokai Publication Sho-54-4191 proposes a vacuum blood collecting tube plug which is provided with a similar elastic backflow prevention valve. The underlying principle of these proposals is that as long as a pressure difference exists between the blood vessel side and the blood collecting tube side, the elastic valve is forced open by the hurriedly incoming blood flow, thus allowing blood collection, but as the pressure difference is abolished, the valve closes to arrest the backflow. However, partly because of the inevitably complicated structures of the blood collecting needle and plug and partly because said pressure difference is inherently small when the blood collecting size setting is small relative to the capacity of the blood collecting tube, the variation in the actual blood collecting size becomes remarkable when a variation occurs in the opening or closing force of the elastic valve.
The present invention, developed to overcome the above-mentioned disadvantages, has for its object to provide a vacuum sampling tube which is capable of preventing a pretreating reagent accommodated in the vacuum sampling tube from entering the blood vessel and the like even in the event of a backflow of a specimen, such as blood, during vacuum sampling, such as vacuum blood collecting, and a vacuum sampling method using said vacuum sampling tube.
A vacuum sampling tube according to the first aspect of the present invention is a sampling vessel comprising
two tubular casings differing in size and each having a closed bottom and an opening at the other end as assembled together in the manner of a nest of boxes,
wherein
1) the inner casing of the nest of boxes is sealed gas-tight at its open end by a gas-barrier, needle hole-sealable plug, whereby a negative pressure state is kept within said casing,
2) the outer casing of the nest of boxes is substantially not in contact with an outer bottom surface of said inner casing of the nest of boxes but is detachably associated at the open end of said outer casing with an outer peripheral surface of said inner casing in the vicinity of its open end in substantially liquid-tight relation, and
3) a specimen-pretreating reagent is accommodated in a space between said inner casing and said outer casing.
A vacuum sampling tube according to the second aspect of the invention is a sampling vessel comprising
a tubular casing having a closed bottom and an opening at the other end and
a cylinder having openings at both ends as assembled in said casing in the manner of a nest of boxes,
wherein
1) the open top end of the inner cylinder of the nest of boxes is sealed gas-tight by a gas-barrier, needle hole-sealable plug,
2) said cylinder is detachably associated, respectively, with the open end of said tubular casing in the vicinity of its open top end in substantially liquid-tight relation and with a plug means of said tubular casing in the vicinity of cylinder""s open bottom end in substantially gas-tight relation,
3) a negative pressure state is kept with in said cylinder, and
4) a specimen-pretreating reagent is accommodated in a space between said cylinder and said tubular casing.
A vacuum sampling tube according to the third aspect of the invention is a sampling vessel comprising
a tubular casing having a closed bottom and an opening at the other end and
a cylinder having openings at both ends as assembled in said casing in the manner of a nest of boxes,
wherein
1) the open top end of the inner cylinder of the nest of boxes is sealed gas-tight by a gas-barrier, needle hole-sealable plug,
2) said cylinder is detachably associated, respectively, with the open end of said tubular casing in the vicinity of its open top end in substantially liquid-tight relation and with a plug means of said tubular casing in the vicinity of cylinder""s open bottom end in substantially gas-tight relation,
3) said open bottom end of the cylinder and said plug means of the tubular casing are provided with complementary notches and, by bringing said cylinder into sliding rotation about its axis, internal spaces of said cylinder and said casing are reversibly brought into communication or out of communication,
4) a negative pressure state is kept within said cylinder, and
5) a specimen-pretreating reagent is accommodated in a space between outer surface of said cylinder and inner surface of said casing.
A vacuum sampling tube according to the fourth aspect of the invention is a sampling vessel comprising
a tubular casing having a closed bottom and an opening at the other end and
a cylinder having openings at both ends as assembled in said casing in the manner of a nest of boxes,
wherein
1) the open top end of the inner cylinder of the nest of boxes is sealed gas-tight by a gas-barrier, needle hole-sealable plug while the open bottom end thereof is sealed gas-tight by a gas-barrier member which can be broken through at least locally, whereby a negative pressure state is kept within said cylinder,
2) said cylinder is designed in such manner that its open bottom end faces a plunger member disposed inwardly of the closed bottom end of said tubular casing, and is detachably and slidably associated with the open end of said tubular casing in substantially liquid-tight relation in the vicinity of its open top end, and
3) a specimen-pretreating reagent is accommodated in a space between outer surface of said cylinder and inner surface of said tubular casing.
A vacuum sampling method according to the fifth aspect of the invention comprises
using the vacuum sampling tube according to the first aspect of the invention and collecting a specimen by vacuum into said inner casing
followed by causing said inner casing to be dissociated from said outer casing, and
adding the specimen in said inner casing to a pretreating reagent in said outer casing.
A vacuum sampling method according to the sixth aspect of the invention comprises
using the vacuum sampling tube according to the second aspect of the invention and collecting a specimen by vacuum into said cylinder
followed by causing said cylinder and said tubular casing to slide axially to dissociate the open bottom end of said cylinder from said plug means,
thereby introducing the specimen in said cylinder into a pretreating reagent in said tubular casing.
The vacuum sampling method according to the seventh aspect of the invention comprises
using the vacuum sampling tube according to the third aspect of the invention and collecting a specimen by vacuum into said cylinder
followed by bringing said cylinder and said tubular casing into relative rotation about the axis to substantially align the notch of the open bottom end of said cylinder with the notch of said plug means,
thereby bringing internal spaces of said cylinder and said casing into communication and
introducing the specimen in said cylinder into a pretreating reagent in said casing.
A vacuum sampling method according to the eighth aspect of the invention comprises
using the vacuum sampling tube according to the fourth aspect of the invention and collecting a specimen by vacuum into said cylinder
followed by pushing said cylinder into said tubular casing to break the breakable member at the bottom end of said cylinder by the plunger member of said tubular casing,
thereby bringing both internal spaces of said cylinder and said casing into communication and
introducing the specimen in said cylinder into a pretreating reagent in said casing.
According to any of the vacuum sampling tubes according to the first through fourth aspects of the invention, since the pretreating reagent which would otherwise find its way into the subject""s body in the event of a backflow is accommodated in a vessel independent of the direct vessel for a vacuum sampling, the risk in the event of a backflow of blood or the like during sampling such as blood collecting can be obviated.
According to any of the vacuum sampling methods according to the fifth through eighth aspects of the invention, since the pretreating reagent which would otherwise finds its way into the subject""s body in the event of a backflow is accommodated in a vessel independent of the direct vessel for a vacuum sampling, the blending of blood or the like with the pretreating reagent takes place after the vacuum sampling, so that the risk in the event of a backflow of blood or the like during sampling such as blood collecting can be obviated.